1. Field of the Invention:
This invention relates to a circuit breaker having a unitary actuating shaft for moving movable contacts in alignment with stationary contacts.
2. Description of the Prior Art:
The so-called "quick-make and quick-break" type of switch is particularly suitable for distribution transformers where the switch contacts are immersed in transformer oil. Such switches are disclosed in U.S. Pat. Nos. 3,461,259 and 3,590,183 and are provided with an overcenter spring mechanism for rotatably moving contact structures for opening and closing circuits. The rotatable moving contact structure comprised a rotatable contact carriage carrying pairs of contact fingers extending outwardly from the rotatable carriage, and making separable engagement with corresponding stationary spaced blade-shaped contacts.
Inasmuch as each opening and closing of the contacts causes vibration of the structure, it sometimes happens that mechanical joints between the several parts including the spring mechanism, the rotatable moving contact structure, and the contacts perse, gradually loosen and develop so-called "slop" in the joints to such an extent that the switch may not open as required.
Associated with the foregoing has been a problem of assembly tolerances. Usually such switches are provided as single or three-phase switches, as required, by the use of housing decks which are detachably added in accordance with the prescribed number of phases. As a result there has been an assembly problem of getting the movable and stationary contacts properly aligned within tolerable limits.